The present invention relates generally to a plastic covering for the anti-corrosion protection of articles and the like. More specifically, the present invention relates to plastic coverings for the repair or sealing of plastic envelopes.
To protect metal pipes, electrical or optical conductors, as well as cables, it is known to surround these articles with hose-like structures of plastic to protect them from environmental influences. These hose-like structures or envelopes are preferably constructed from polyolefins.
Although these envelopes do protect the covered article from the corrosive effects of the environment, they are, however, subject to a risk that they can be damaged by mechanical forces and influences. This thereby limits the usefulness of the envelopes in protecting articles and the like. Once the envelope has been damaged by, for example, a mechanical force, the envelope must be repaired in order to restore the protective functions of the envelope.
Typically, repair bands are used to repair the envelope. These repair bands are usually composed of a cross-linked polyolefin foil coated on one side with a hot-melt adhesive. Examples of such repair bands are described in, for example, German Patent Application No. 22 50 096 and U.S. Pat. No. 3,033,727. The suitabilily and reliability of these commercially available repair bands depends, to a great extent, on the quality of the adhesion, or gluing, of the band to the corresponding foundation of the envelope. Moreover, because the connection of the repair band to the envelope is based on the adhesion of the repair band to the envelope it is greatly dependent on temperature fluctuations. At high temperatures, there is a risk of a separation of the band from the envelope due to a softening of the hot-melt adhesive used to secure the band to the envelope. At low temperatures, an embrittlement of the adhesive can occur and can lead to a separation of the repair band from the envelope or at least to a loss of the strength of the seal of the repair band to the envelope.
There is therefore a need for an improved plastic covering for repairing and sealing envelopes that provide an anti-corrosion protection to articles and the like.